Friday, February 1, 2013
Goldilocks and Digital Sculpting
After a few weeks of doing a lot of traditional sculpting, I took a few days to work on a few digital ideas I have for 3D printing. The big issue I was working out was how to increase the smoothness of the model when printed but still keep the sharp edges where I need them.
Blender's subsurface division modifier will create new faces and smooth the overall model, but it's quirky. It has some predetermined method of weighting vertices that creates weird artifacts where you'd least expect them. Or where I don't want them anyway.
My first few attempts were on a Monkey Boy corsair. I had an idea of the shape and characteristics and set about modeling it.
I wanted it to ape the simian form a little. Roughly head-shaped cockpit, large cargo area chest and dangling arm-like wings.
Smoothing the various forms was easy using the sub-surf modifier. However, I had to work out how to keep some sharper creases so that it didn't become too sleek and rounded looking.
This was accomplished by the use of control loops. These are an extra set of edges set just inside the outer edge of the corner that needs to be sharpened. You can see the effect on the edges of the wing when compared to the cockpit.
Ok, enough play with that for a while. On to some simpler items that I actually want to have printed for production.
I haven't seen fire hydrants. So I worked up a drawing with all the smooth places smooth and all the sharp places sharpened.
Parking meters were another item I wanted for my game table.
So I made a double and a single version.
I sprued them together and sent it off for a quote. The file size is five times too large to work on the machine. All of those extra little faces to smooth things add bulk to the data block. Converting the data to .stl format also about doubles the faces since it changes all quad surfaces to triangles. 151mb of unprintable goodness. back to the drawing board on that one.
All right, I'll work on something that has a combination of shapes. It's a little bit more simple. And I can cut down the amount of faces to see how many I actually need when the models are scaled down, molded and cast in white metal.
On to some VSF work. I present the Hotchkiss 1 lb rotary cannon for all of your Victorian rapid fire destructive needs.
It's simplified a bit and some internal spaces are filled for casting.
And of course we need a mount of some sort. The easiest to model was the naval pedestal.
So again, I put them on a sprue and sent them off for a quote.
This time dude tells me he'd recommend more smoothing. I explained to him that I really just need to see how they turn out since they'll be so small. Will the faceting matter? But wait... what if I want to scale them up for other gaming sizes? I know, I'll redo the drawing and sprue both together so I can see them side by side during each step of the production.
What I really need is my own printer so I can get immediate feedback. But until that time comes, back to the drawing board. And back to pushing the putty that I set aside for a bit.